A Constellation of Fluorescent Biosensors to Illuminate the Galaxy of Protein Kinases

Protein kinases (PKs) are enzymes that catalyze phosphorylation of protein substrates involved in a wide variety of biological signalling pathways. PKs can be distinguished based on their mechanism of action and their regulation. They are associated with numerous pathologies, thereby constituting attractive biomarkers and targets for development of therapeutics. Given their importance, a wide variety of strategies and technologies have been devised for their detection, their quantification, and for studying their dynamic behavior, from radioactive and antibody-based approaches to biochemical, kinomic, and biosensing technologies. A wide variety of fluorescent biosensors have been tailored to report on PK activities in vitro and for imaging purposes. These tools allow researchers to monitor PK activities in a highly sensitive and dynamic fashion in complex samples, providing new avenues for investigating PK behavior in native conditions and following stimulation or inhibition with drugs, thereby providing functional information which complements genetic, transcriptomic, or proteomic approaches. This review focuses on the different families of PKs and on fluorescent biosensors and chemosensors available to report, profile and image PKs from the AGC, CMGC, CAMK, TK, and TKL kinases.